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Message-ID: <20190417175320.GA17872@roeck-us.net>
Date: Wed, 17 Apr 2019 10:53:20 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
Cc: Linux Doc Mailing List <linux-doc@...r.kernel.org>,
Mauro Carvalho Chehab <mchehab@...radead.org>,
linux-kernel@...r.kernel.org, Jonathan Corbet <corbet@....net>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
linux-watchdog@...r.kernel.org
Subject: Re: [PATCH 37/57] docs: watchdog: convert documents to ReST format
On Mon, Apr 15, 2019 at 11:56:02PM -0300, Mauro Carvalho Chehab wrote:
> Convert those documents and prepare them to be part of the kernel
> API book, as most of the stuff there are related to the
> Kernel interfaces.
>
> Still, in the future, it would make sense to split the docs,
> as some of the stuff is clearly focused on sysadmin tasks.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
What is the plan here ? Submit through watchdog subsystem or through
some other subsystem ? Also, will the files be renamed ?
Thanks,
Guenter
> ---
> .../convert_drivers_to_kernel_api.txt | 109 +--
> Documentation/watchdog/hpwdt.txt | 23 +-
> Documentation/watchdog/mlx-wdt.txt | 24 +-
> Documentation/watchdog/pcwd-watchdog.txt | 13 +-
> Documentation/watchdog/watchdog-api.txt | 76 +-
> .../watchdog/watchdog-kernel-api.txt | 89 ++-
> .../watchdog/watchdog-parameters.txt | 672 +++++++++++++-----
> Documentation/watchdog/watchdog-pm.txt | 3 +
> Documentation/watchdog/wdt.txt | 31 +-
> 9 files changed, 733 insertions(+), 307 deletions(-)
>
> diff --git a/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
> index 9fffb2958d13..dd934cc08e40 100644
> --- a/Documentation/watchdog/convert_drivers_to_kernel_api.txt
> +++ b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
> @@ -1,6 +1,8 @@
> +=========================================================
> Converting old watchdog drivers to the watchdog framework
> +=========================================================
> +
> by Wolfram Sang <w.sang@...gutronix.de>
> -=========================================================
>
> Before the watchdog framework came into the kernel, every driver had to
> implement the API on its own. Now, as the framework factored out the common
> @@ -69,16 +71,16 @@ Here is a overview of the functions and probably needed actions:
> -ENOIOCTLCMD, the IOCTLs of the framework will be tried, too. Any other error
> is directly given to the user.
>
> -Example conversion:
> +Example conversion::
>
> --static const struct file_operations s3c2410wdt_fops = {
> -- .owner = THIS_MODULE,
> -- .llseek = no_llseek,
> -- .write = s3c2410wdt_write,
> -- .unlocked_ioctl = s3c2410wdt_ioctl,
> -- .open = s3c2410wdt_open,
> -- .release = s3c2410wdt_release,
> --};
> + -static const struct file_operations s3c2410wdt_fops = {
> + - .owner = THIS_MODULE,
> + - .llseek = no_llseek,
> + - .write = s3c2410wdt_write,
> + - .unlocked_ioctl = s3c2410wdt_ioctl,
> + - .open = s3c2410wdt_open,
> + - .release = s3c2410wdt_release,
> + -};
>
> Check the functions for device-specific stuff and keep it for later
> refactoring. The rest can go.
> @@ -89,24 +91,24 @@ Remove the miscdevice
>
> Since the file_operations are gone now, you can also remove the 'struct
> miscdevice'. The framework will create it on watchdog_dev_register() called by
> -watchdog_register_device().
> +watchdog_register_device()::
>
> --static struct miscdevice s3c2410wdt_miscdev = {
> -- .minor = WATCHDOG_MINOR,
> -- .name = "watchdog",
> -- .fops = &s3c2410wdt_fops,
> --};
> + -static struct miscdevice s3c2410wdt_miscdev = {
> + - .minor = WATCHDOG_MINOR,
> + - .name = "watchdog",
> + - .fops = &s3c2410wdt_fops,
> + -};
>
>
> Remove obsolete includes and defines
> ------------------------------------
>
> Because of the simplifications, a few defines are probably unused now. Remove
> -them. Includes can be removed, too. For example:
> +them. Includes can be removed, too. For example::
>
> -- #include <linux/fs.h>
> -- #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used)
> -- #include <linux/uaccess.h> (if no custom IOCTLs are used)
> + - #include <linux/fs.h>
> + - #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used)
> + - #include <linux/uaccess.h> (if no custom IOCTLs are used)
>
>
> Add the watchdog operations
> @@ -121,30 +123,30 @@ change the function header. Other changes are most likely not needed, because
> here simply happens the direct hardware access. If you have device-specific
> code left from the above steps, it should be refactored into these callbacks.
>
> -Here is a simple example:
> +Here is a simple example::
>
> -+static struct watchdog_ops s3c2410wdt_ops = {
> -+ .owner = THIS_MODULE,
> -+ .start = s3c2410wdt_start,
> -+ .stop = s3c2410wdt_stop,
> -+ .ping = s3c2410wdt_keepalive,
> -+ .set_timeout = s3c2410wdt_set_heartbeat,
> -+};
> + +static struct watchdog_ops s3c2410wdt_ops = {
> + + .owner = THIS_MODULE,
> + + .start = s3c2410wdt_start,
> + + .stop = s3c2410wdt_stop,
> + + .ping = s3c2410wdt_keepalive,
> + + .set_timeout = s3c2410wdt_set_heartbeat,
> + +};
>
> -A typical function-header change looks like:
> +A typical function-header change looks like::
>
> --static void s3c2410wdt_keepalive(void)
> -+static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
> - {
> -...
> -+
> -+ return 0;
> - }
> + -static void s3c2410wdt_keepalive(void)
> + +static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
> + {
> + ...
> + +
> + + return 0;
> + }
>
> -...
> + ...
>
> -- s3c2410wdt_keepalive();
> -+ s3c2410wdt_keepalive(&s3c2410_wdd);
> + - s3c2410wdt_keepalive();
> + + s3c2410wdt_keepalive(&s3c2410_wdd);
>
>
> Add the watchdog device
> @@ -159,12 +161,12 @@ static variables. Those have to be converted to use the members in
> watchdog_device. Note that the timeout values are unsigned int. Some drivers
> use signed int, so this has to be converted, too.
>
> -Here is a simple example for a watchdog device:
> +Here is a simple example for a watchdog device::
>
> -+static struct watchdog_device s3c2410_wdd = {
> -+ .info = &s3c2410_wdt_ident,
> -+ .ops = &s3c2410wdt_ops,
> -+};
> + +static struct watchdog_device s3c2410_wdd = {
> + + .info = &s3c2410_wdt_ident,
> + + .ops = &s3c2410wdt_ops,
> + +};
>
>
> Handle the 'nowayout' feature
> @@ -173,12 +175,12 @@ Handle the 'nowayout' feature
> A few drivers use nowayout statically, i.e. there is no module parameter for it
> and only CONFIG_WATCHDOG_NOWAYOUT determines if the feature is going to be
> used. This needs to be converted by initializing the status variable of the
> -watchdog_device like this:
> +watchdog_device like this::
>
> .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
>
> Most drivers, however, also allow runtime configuration of nowayout, usually
> -by adding a module parameter. The conversion for this would be something like:
> +by adding a module parameter. The conversion for this would be something like::
>
> watchdog_set_nowayout(&s3c2410_wdd, nowayout);
>
> @@ -191,15 +193,15 @@ Register the watchdog device
>
> Replace misc_register(&miscdev) with watchdog_register_device(&watchdog_dev).
> Make sure the return value gets checked and the error message, if present,
> -still fits. Also convert the unregister case.
> +still fits. Also convert the unregister case::
>
> -- ret = misc_register(&s3c2410wdt_miscdev);
> -+ ret = watchdog_register_device(&s3c2410_wdd);
> + - ret = misc_register(&s3c2410wdt_miscdev);
> + + ret = watchdog_register_device(&s3c2410_wdd);
>
> -...
> + ...
>
> -- misc_deregister(&s3c2410wdt_miscdev);
> -+ watchdog_unregister_device(&s3c2410_wdd);
> + - misc_deregister(&s3c2410wdt_miscdev);
> + + watchdog_unregister_device(&s3c2410_wdd);
>
>
> Update the Kconfig-entry
> @@ -207,7 +209,7 @@ Update the Kconfig-entry
>
> The entry for the driver now needs to select WATCHDOG_CORE:
>
> -+ select WATCHDOG_CORE
> + + select WATCHDOG_CORE
>
>
> Create a patch and send it to upstream
> @@ -215,4 +217,3 @@ Create a patch and send it to upstream
>
> Make sure you understood Documentation/process/submitting-patches.rst and send your patch to
> linux-watchdog@...r.kernel.org. We are looking forward to it :)
> -
> diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt
> index 55df692c5595..a8c6751321de 100644
> --- a/Documentation/watchdog/hpwdt.txt
> +++ b/Documentation/watchdog/hpwdt.txt
> @@ -1,7 +1,12 @@
> +===========================
> +HPE iLO NMI Watchdog Driver
> +===========================
> +
> +for iLO based ProLiant Servers
> +==============================
> +
> Last reviewed: 08/20/2018
>
> - HPE iLO NMI Watchdog Driver
> - for iLO based ProLiant Servers
>
> The HPE iLO NMI Watchdog driver is a kernel module that provides basic
> watchdog functionality and handler for the iLO "Generate NMI to System"
> @@ -20,21 +25,24 @@ Last reviewed: 08/20/2018
>
> The hpwdt driver also has the following module parameters:
>
> - soft_margin - allows the user to set the watchdog timer value.
> + ============ ================================================================
> + soft_margin allows the user to set the watchdog timer value.
> Default value is 30 seconds.
> - timeout - an alias of soft_margin.
> - pretimeout - allows the user to set the watchdog pretimeout value.
> + timeout an alias of soft_margin.
> + pretimeout allows the user to set the watchdog pretimeout value.
> This is the number of seconds before timeout when an
> NMI is delivered to the system. Setting the value to
> zero disables the pretimeout NMI.
> Default value is 9 seconds.
> - nowayout - basic watchdog parameter that does not allow the timer to
> + nowayout basic watchdog parameter that does not allow the timer to
> be restarted or an impending ASR to be escaped.
> Default value is set when compiling the kernel. If it is set
> to "Y", then there is no way of disabling the watchdog once
> it has been started.
> + ============ ================================================================
>
> - NOTE: More information about watchdog drivers in general, including the ioctl
> + NOTE:
> + More information about watchdog drivers in general, including the ioctl
> interface to /dev/watchdog can be found in
> Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt.
>
> @@ -63,4 +71,3 @@ Last reviewed: 08/20/2018
>
> The HPE iLO NMI Watchdog Driver and documentation were originally developed
> by Tom Mingarelli.
> -
> diff --git a/Documentation/watchdog/mlx-wdt.txt b/Documentation/watchdog/mlx-wdt.txt
> index 66eeb78505c3..bf5bafac47f0 100644
> --- a/Documentation/watchdog/mlx-wdt.txt
> +++ b/Documentation/watchdog/mlx-wdt.txt
> @@ -1,5 +1,9 @@
> - Mellanox watchdog drivers
> - for x86 based system switches
> +=========================
> +Mellanox watchdog drivers
> +=========================
> +
> +for x86 based system switches
> +=============================
>
> This driver provides watchdog functionality for various Mellanox
> Ethernet and Infiniband switch systems.
> @@ -9,16 +13,16 @@ Mellanox watchdog device is implemented in a programmable logic device.
> There are 2 types of HW watchdog implementations.
>
> Type 1:
> -Actual HW timeout can be defined as a power of 2 msec.
> -e.g. timeout 20 sec will be rounded up to 32768 msec.
> -The maximum timeout period is 32 sec (32768 msec.),
> -Get time-left isn't supported
> + Actual HW timeout can be defined as a power of 2 msec.
> + e.g. timeout 20 sec will be rounded up to 32768 msec.
> + The maximum timeout period is 32 sec (32768 msec.),
> + Get time-left isn't supported
>
> Type 2:
> -Actual HW timeout is defined in sec. and it's the same as
> -a user-defined timeout.
> -Maximum timeout is 255 sec.
> -Get time-left is supported.
> + Actual HW timeout is defined in sec. and it's the same as
> + a user-defined timeout.
> + Maximum timeout is 255 sec.
> + Get time-left is supported.
>
> Type 1 HW watchdog implementation exist in old systems and
> all new systems have type 2 HW watchdog.
> diff --git a/Documentation/watchdog/pcwd-watchdog.txt b/Documentation/watchdog/pcwd-watchdog.txt
> index b8e60a441a43..405e2a370082 100644
> --- a/Documentation/watchdog/pcwd-watchdog.txt
> +++ b/Documentation/watchdog/pcwd-watchdog.txt
> @@ -1,8 +1,13 @@
> +===================================
> +Berkshire Products PC Watchdog Card
> +===================================
> +
> Last reviewed: 10/05/2007
>
> - Berkshire Products PC Watchdog Card
> - Support for ISA Cards Revision A and C
> - Documentation and Driver by Ken Hollis <kenji@...gate.com>
> +Support for ISA Cards Revision A and C
> +=======================================
> +
> +Documentation and Driver by Ken Hollis <kenji@...gate.com>
>
> The PC Watchdog is a card that offers the same type of functionality that
> the WDT card does, only it doesn't require an IRQ to run. Furthermore,
> @@ -33,6 +38,7 @@ Last reviewed: 10/05/2007
> WDIOC_GETSUPPORT
> This returns the support of the card itself. This
> returns in structure "PCWDS" which returns:
> +
> options = WDIOS_TEMPPANIC
> (This card supports temperature)
> firmware_version = xxxx
> @@ -63,4 +69,3 @@ Last reviewed: 10/05/2007
>
> -- Ken Hollis
> (kenji@...gate.com)
> -
> diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt
> index 0e62ba33b7fb..c6c1e9fa9f73 100644
> --- a/Documentation/watchdog/watchdog-api.txt
> +++ b/Documentation/watchdog/watchdog-api.txt
> @@ -1,7 +1,10 @@
> +=============================
> +The Linux Watchdog driver API
> +=============================
> +
> Last reviewed: 10/05/2007
>
>
> -The Linux Watchdog driver API.
>
> Copyright 2002 Christer Weingel <wingel@...o-system.com>
>
> @@ -10,7 +13,8 @@ driver which is (c) Copyright 2000 Jakob Oestergaard <jakob@...enfeld.dk>
>
> This document describes the state of the Linux 2.4.18 kernel.
>
> -Introduction:
> +Introduction
> +============
>
> A Watchdog Timer (WDT) is a hardware circuit that can reset the
> computer system in case of a software fault. You probably knew that
> @@ -30,7 +34,8 @@ drivers implement different, and sometimes incompatible, parts of it.
> This file is an attempt to document the existing usage and allow
> future driver writers to use it as a reference.
>
> -The simplest API:
> +The simplest API
> +================
>
> All drivers support the basic mode of operation, where the watchdog
> activates as soon as /dev/watchdog is opened and will reboot unless
> @@ -54,7 +59,8 @@ after the timeout has passed. Watchdog devices also usually support
> the nowayout module parameter so that this option can be controlled at
> runtime.
>
> -Magic Close feature:
> +Magic Close feature
> +===================
>
> If a driver supports "Magic Close", the driver will not disable the
> watchdog unless a specific magic character 'V' has been sent to
> @@ -64,7 +70,8 @@ will assume that the daemon (and userspace in general) died, and will
> stop pinging the watchdog without disabling it first. This will then
> cause a reboot if the watchdog is not re-opened in sufficient time.
>
> -The ioctl API:
> +The ioctl API
> +=============
>
> All conforming drivers also support an ioctl API.
>
> @@ -73,7 +80,7 @@ Pinging the watchdog using an ioctl:
> All drivers that have an ioctl interface support at least one ioctl,
> KEEPALIVE. This ioctl does exactly the same thing as a write to the
> watchdog device, so the main loop in the above program could be
> -replaced with:
> +replaced with::
>
> while (1) {
> ioctl(fd, WDIOC_KEEPALIVE, 0);
> @@ -82,14 +89,15 @@ replaced with:
>
> the argument to the ioctl is ignored.
>
> -Setting and getting the timeout:
> +Setting and getting the timeout
> +===============================
>
> For some drivers it is possible to modify the watchdog timeout on the
> fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT
> flag set in their option field. The argument is an integer
> representing the timeout in seconds. The driver returns the real
> timeout used in the same variable, and this timeout might differ from
> -the requested one due to limitation of the hardware.
> +the requested one due to limitation of the hardware::
>
> int timeout = 45;
> ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
> @@ -99,18 +107,19 @@ This example might actually print "The timeout was set to 60 seconds"
> if the device has a granularity of minutes for its timeout.
>
> Starting with the Linux 2.4.18 kernel, it is possible to query the
> -current timeout using the GETTIMEOUT ioctl.
> +current timeout using the GETTIMEOUT ioctl::
>
> ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
> printf("The timeout was is %d seconds\n", timeout);
>
> -Pretimeouts:
> +Pretimeouts
> +===========
>
> Some watchdog timers can be set to have a trigger go off before the
> actual time they will reset the system. This can be done with an NMI,
> interrupt, or other mechanism. This allows Linux to record useful
> information (like panic information and kernel coredumps) before it
> -resets.
> +resets::
>
> pretimeout = 10;
> ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
> @@ -121,89 +130,113 @@ the pretimeout. So, for instance, if you set the timeout to 60 seconds
> and the pretimeout to 10 seconds, the pretimeout will go off in 50
> seconds. Setting a pretimeout to zero disables it.
>
> -There is also a get function for getting the pretimeout:
> +There is also a get function for getting the pretimeout::
>
> ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
> printf("The pretimeout was is %d seconds\n", timeout);
>
> Not all watchdog drivers will support a pretimeout.
>
> -Get the number of seconds before reboot:
> +Get the number of seconds before reboot
> +=======================================
>
> Some watchdog drivers have the ability to report the remaining time
> before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl
> -that returns the number of seconds before reboot.
> +that returns the number of seconds before reboot::
>
> ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
> printf("The timeout was is %d seconds\n", timeleft);
>
> -Environmental monitoring:
> +Environmental monitoring
> +========================
>
> All watchdog drivers are required return more information about the system,
> some do temperature, fan and power level monitoring, some can tell you
> the reason for the last reboot of the system. The GETSUPPORT ioctl is
> -available to ask what the device can do:
> +available to ask what the device can do::
>
> struct watchdog_info ident;
> ioctl(fd, WDIOC_GETSUPPORT, &ident);
>
> the fields returned in the ident struct are:
>
> + ================ =============================================
> identity a string identifying the watchdog driver
> firmware_version the firmware version of the card if available
> options a flags describing what the device supports
> + ================ =============================================
>
> the options field can have the following bits set, and describes what
> kind of information that the GET_STATUS and GET_BOOT_STATUS ioctls can
> return. [FIXME -- Is this correct?]
>
> + ================ =========================
> WDIOF_OVERHEAT Reset due to CPU overheat
> + ================ =========================
>
> The machine was last rebooted by the watchdog because the thermal limit was
> -exceeded
> +exceeded:
>
> + ============== ==========
> WDIOF_FANFAULT Fan failed
> + ============== ==========
>
> A system fan monitored by the watchdog card has failed
>
> + ============= ================
> WDIOF_EXTERN1 External relay 1
> + ============= ================
>
> External monitoring relay/source 1 was triggered. Controllers intended for
> real world applications include external monitoring pins that will trigger
> a reset.
>
> + ============= ================
> WDIOF_EXTERN2 External relay 2
> + ============= ================
>
> External monitoring relay/source 2 was triggered
>
> + ================ =====================
> WDIOF_POWERUNDER Power bad/power fault
> + ================ =====================
>
> The machine is showing an undervoltage status
>
> + =============== =============================
> WDIOF_CARDRESET Card previously reset the CPU
> + =============== =============================
>
> The last reboot was caused by the watchdog card
>
> + ================ =====================
> WDIOF_POWEROVER Power over voltage
> + ================ =====================
>
> The machine is showing an overvoltage status. Note that if one level is
> under and one over both bits will be set - this may seem odd but makes
> sense.
>
> + =================== =====================
> WDIOF_KEEPALIVEPING Keep alive ping reply
> + =================== =====================
>
> The watchdog saw a keepalive ping since it was last queried.
>
> + ================ =======================
> WDIOF_SETTIMEOUT Can set/get the timeout
> + ================ =======================
>
> The watchdog can do pretimeouts.
>
> + ================ ================================
> WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set
> + ================ ================================
>
>
> For those drivers that return any bits set in the option field, the
> GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current
> -status, and the status at the last reboot, respectively.
> +status, and the status at the last reboot, respectively::
>
> int flags;
> ioctl(fd, WDIOC_GETSTATUS, &flags);
> @@ -216,22 +249,23 @@ Note that not all devices support these two calls, and some only
> support the GETBOOTSTATUS call.
>
> Some drivers can measure the temperature using the GETTEMP ioctl. The
> -returned value is the temperature in degrees fahrenheit.
> +returned value is the temperature in degrees fahrenheit::
>
> int temperature;
> ioctl(fd, WDIOC_GETTEMP, &temperature);
>
> Finally the SETOPTIONS ioctl can be used to control some aspects of
> -the cards operation.
> +the cards operation::
>
> int options = 0;
> ioctl(fd, WDIOC_SETOPTIONS, &options);
>
> The following options are available:
>
> + ================= ================================
> WDIOS_DISABLECARD Turn off the watchdog timer
> WDIOS_ENABLECARD Turn on the watchdog timer
> WDIOS_TEMPPANIC Kernel panic on temperature trip
> + ================= ================================
>
> [FIXME -- better explanations]
> -
> diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
> index 3a91ef5af044..452002be568c 100644
> --- a/Documentation/watchdog/watchdog-kernel-api.txt
> +++ b/Documentation/watchdog/watchdog-kernel-api.txt
> @@ -1,5 +1,7 @@
> -The Linux WatchDog Timer Driver Core kernel API.
> ===============================================
> +The Linux WatchDog Timer Driver Core kernel API
> +===============================================
> +
> Last reviewed: 12-Feb-2013
>
> Wim Van Sebroeck <wim@...ana.be>
> @@ -23,10 +25,10 @@ The API
> Each watchdog timer driver that wants to use the WatchDog Timer Driver Core
> must #include <linux/watchdog.h> (you would have to do this anyway when
> writing a watchdog device driver). This include file contains following
> -register/unregister routines:
> +register/unregister routines::
>
> -extern int watchdog_register_device(struct watchdog_device *);
> -extern void watchdog_unregister_device(struct watchdog_device *);
> + extern int watchdog_register_device(struct watchdog_device *);
> + extern void watchdog_unregister_device(struct watchdog_device *);
>
> The watchdog_register_device routine registers a watchdog timer device.
> The parameter of this routine is a pointer to a watchdog_device structure.
> @@ -40,9 +42,9 @@ The watchdog subsystem includes an registration deferral mechanism,
> which allows you to register an watchdog as early as you wish during
> the boot process.
>
> -The watchdog device structure looks like this:
> +The watchdog device structure looks like this::
>
> -struct watchdog_device {
> + struct watchdog_device {
> int id;
> struct device *parent;
> const struct attribute_group **groups;
> @@ -62,9 +64,10 @@ struct watchdog_device {
> struct watchdog_core_data *wd_data;
> unsigned long status;
> struct list_head deferred;
> -};
> + };
>
> It contains following fields:
> +
> * id: set by watchdog_register_device, id 0 is special. It has both a
> /dev/watchdog0 cdev (dynamic major, minor 0) as well as the old
> /dev/watchdog miscdev. The id is set automatically when calling
> @@ -114,9 +117,9 @@ It contains following fields:
> * deferred: entry in wtd_deferred_reg_list which is used to
> register early initialized watchdogs.
>
> -The list of watchdog operations is defined as:
> +The list of watchdog operations is defined as::
>
> -struct watchdog_ops {
> + struct watchdog_ops {
> struct module *owner;
> /* mandatory operations */
> int (*start)(struct watchdog_device *);
> @@ -129,7 +132,7 @@ struct watchdog_ops {
> unsigned int (*get_timeleft)(struct watchdog_device *);
> int (*restart)(struct watchdog_device *);
> long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
> -};
> + };
>
> It is important that you first define the module owner of the watchdog timer
> driver's operations. This module owner will be used to lock the module when
> @@ -138,6 +141,7 @@ module and /dev/watchdog is still open).
>
> Some operations are mandatory and some are optional. The mandatory operations
> are:
> +
> * start: this is a pointer to the routine that starts the watchdog timer
> device.
> The routine needs a pointer to the watchdog timer device structure as a
> @@ -146,51 +150,64 @@ are:
> Not all watchdog timer hardware supports the same functionality. That's why
> all other routines/operations are optional. They only need to be provided if
> they are supported. These optional routines/operations are:
> +
> * stop: with this routine the watchdog timer device is being stopped.
> +
> The routine needs a pointer to the watchdog timer device structure as a
> parameter. It returns zero on success or a negative errno code for failure.
> Some watchdog timer hardware can only be started and not be stopped. A
> driver supporting such hardware does not have to implement the stop routine.
> +
> If a driver has no stop function, the watchdog core will set WDOG_HW_RUNNING
> and start calling the driver's keepalive pings function after the watchdog
> device is closed.
> +
> If a watchdog driver does not implement the stop function, it must set
> max_hw_heartbeat_ms.
> * ping: this is the routine that sends a keepalive ping to the watchdog timer
> hardware.
> +
> The routine needs a pointer to the watchdog timer device structure as a
> parameter. It returns zero on success or a negative errno code for failure.
> +
> Most hardware that does not support this as a separate function uses the
> start function to restart the watchdog timer hardware. And that's also what
> the watchdog timer driver core does: to send a keepalive ping to the watchdog
> timer hardware it will either use the ping operation (when available) or the
> start operation (when the ping operation is not available).
> +
> (Note: the WDIOC_KEEPALIVE ioctl call will only be active when the
> WDIOF_KEEPALIVEPING bit has been set in the option field on the watchdog's
> info structure).
> * status: this routine checks the status of the watchdog timer device. The
> status of the device is reported with watchdog WDIOF_* status flags/bits.
> +
> WDIOF_MAGICCLOSE and WDIOF_KEEPALIVEPING are reported by the watchdog core;
> it is not necessary to report those bits from the driver. Also, if no status
> function is provided by the driver, the watchdog core reports the status bits
> provided in the bootstatus variable of struct watchdog_device.
> +
> * set_timeout: this routine checks and changes the timeout of the watchdog
> timer device. It returns 0 on success, -EINVAL for "parameter out of range"
> and -EIO for "could not write value to the watchdog". On success this
> routine should set the timeout value of the watchdog_device to the
> achieved timeout value (which may be different from the requested one
> because the watchdog does not necessarily have a 1 second resolution).
> +
> Drivers implementing max_hw_heartbeat_ms set the hardware watchdog heartbeat
> to the minimum of timeout and max_hw_heartbeat_ms. Those drivers set the
> timeout value of the watchdog_device either to the requested timeout value
> (if it is larger than max_hw_heartbeat_ms), or to the achieved timeout value.
> (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
> watchdog's info structure).
> +
> If the watchdog driver does not have to perform any action but setting the
> watchdog_device.timeout, this callback can be omitted.
> +
> If set_timeout is not provided but, WDIOF_SETTIMEOUT is set, the watchdog
> infrastructure updates the timeout value of the watchdog_device internally
> to the requested value.
> +
> If the pretimeout feature is used (WDIOF_PRETIMEOUT), then set_timeout must
> also take care of checking if pretimeout is still valid and set up the timer
> accordingly. This can't be done in the core without races, so it is the
> @@ -201,13 +218,16 @@ they are supported. These optional routines/operations are:
> seconds before the actual timeout would happen. It returns 0 on success,
> -EINVAL for "parameter out of range" and -EIO for "could not write value to
> the watchdog". A value of 0 disables pretimeout notification.
> +
> (Note: the WDIOF_PRETIMEOUT needs to be set in the options field of the
> watchdog's info structure).
> +
> If the watchdog driver does not have to perform any action but setting the
> watchdog_device.pretimeout, this callback can be omitted. That means if
> set_pretimeout is not provided but WDIOF_PRETIMEOUT is set, the watchdog
> infrastructure updates the pretimeout value of the watchdog_device internally
> to the requested value.
> +
> * get_timeleft: this routines returns the time that's left before a reset.
> * restart: this routine restarts the machine. It returns 0 on success or a
> negative errno code for failure.
> @@ -218,6 +238,7 @@ they are supported. These optional routines/operations are:
>
> The status bits should (preferably) be set with the set_bit and clear_bit alike
> bit-operations. The status bits that are defined are:
> +
> * WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device
> is active or not from user perspective. User space is expected to send
> heartbeat requests to the driver while this flag is set.
> @@ -235,22 +256,30 @@ bit-operations. The status bits that are defined are:
>
> To set the WDOG_NO_WAY_OUT status bit (before registering your watchdog
> timer device) you can either:
> +
> * set it statically in your watchdog_device struct with
> +
> .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
> +
> (this will set the value the same as CONFIG_WATCHDOG_NOWAYOUT) or
> - * use the following helper function:
> - static inline void watchdog_set_nowayout(struct watchdog_device *wdd, int nowayout)
> + * use the following helper function::
> +
> + static inline void watchdog_set_nowayout(struct watchdog_device *wdd,
> + int nowayout)
> +
> +Note:
> + The WatchDog Timer Driver Core supports the magic close feature and
> + the nowayout feature. To use the magic close feature you must set the
> + WDIOF_MAGICCLOSE bit in the options field of the watchdog's info structure.
>
> -Note: The WatchDog Timer Driver Core supports the magic close feature and
> -the nowayout feature. To use the magic close feature you must set the
> -WDIOF_MAGICCLOSE bit in the options field of the watchdog's info structure.
> The nowayout feature will overrule the magic close feature.
>
> To get or set driver specific data the following two helper functions should be
> -used:
> +used::
>
> -static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
> -static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
> + static inline void watchdog_set_drvdata(struct watchdog_device *wdd,
> + void *data)
> + static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
>
> The watchdog_set_drvdata function allows you to add driver specific data. The
> arguments of this function are the watchdog device where you want to add the
> @@ -260,10 +289,11 @@ The watchdog_get_drvdata function allows you to retrieve driver specific data.
> The argument of this function is the watchdog device where you want to retrieve
> data from. The function returns the pointer to the driver specific data.
>
> -To initialize the timeout field, the following function can be used:
> +To initialize the timeout field, the following function can be used::
>
> -extern int watchdog_init_timeout(struct watchdog_device *wdd,
> - unsigned int timeout_parm, struct device *dev);
> + extern int watchdog_init_timeout(struct watchdog_device *wdd,
> + unsigned int timeout_parm,
> + struct device *dev);
>
> The watchdog_init_timeout function allows you to initialize the timeout field
> using the module timeout parameter or by retrieving the timeout-sec property from
> @@ -272,30 +302,33 @@ to set the default timeout value as timeout value in the watchdog_device and
> then use this function to set the user "preferred" timeout value.
> This routine returns zero on success and a negative errno code for failure.
>
> -To disable the watchdog on reboot, the user must call the following helper:
> +To disable the watchdog on reboot, the user must call the following helper::
>
> -static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd);
> + static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd);
>
> To disable the watchdog when unregistering the watchdog, the user must call
> the following helper. Note that this will only stop the watchdog if the
> nowayout flag is not set.
>
> -static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd);
> +::
> +
> + static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd);
>
> To change the priority of the restart handler the following helper should be
> -used:
> +used::
>
> -void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
> + void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
>
> User should follow the following guidelines for setting the priority:
> +
> * 0: should be called in last resort, has limited restart capabilities
> * 128: default restart handler, use if no other handler is expected to be
> available, and/or if restart is sufficient to restart the entire system
> * 255: highest priority, will preempt all other restart handlers
>
> -To raise a pretimeout notification, the following function should be used:
> +To raise a pretimeout notification, the following function should be used::
>
> -void watchdog_notify_pretimeout(struct watchdog_device *wdd)
> + void watchdog_notify_pretimeout(struct watchdog_device *wdd)
>
> The function can be called in the interrupt context. If watchdog pretimeout
> governor framework (kbuild CONFIG_WATCHDOG_PRETIMEOUT_GOV symbol) is enabled,
> diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
> index 0b88e333f9e1..b121caae7798 100644
> --- a/Documentation/watchdog/watchdog-parameters.txt
> +++ b/Documentation/watchdog/watchdog-parameters.txt
> @@ -1,410 +1,736 @@
> +==========================
> +WatchDog Module Parameters
> +==========================
> +
> This file provides information on the module parameters of many of
> the Linux watchdog drivers. Watchdog driver parameter specs should
> be listed here unless the driver has its own driver-specific information
> file.
>
> -
> See Documentation/admin-guide/kernel-parameters.rst for information on
> providing kernel parameters for builtin drivers versus loadable
> modules.
>
> -
> -------------------------------------------------
> +
> acquirewdt:
> -wdt_stop: Acquire WDT 'stop' io port (default 0x43)
> -wdt_start: Acquire WDT 'start' io port (default 0x443)
> -nowayout: Watchdog cannot be stopped once started
> + wdt_stop:
> + Acquire WDT 'stop' io port (default 0x43)
> + wdt_start:
> + Acquire WDT 'start' io port (default 0x443)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> advantechwdt:
> -wdt_stop: Advantech WDT 'stop' io port (default 0x443)
> -wdt_start: Advantech WDT 'start' io port (default 0x443)
> -timeout: Watchdog timeout in seconds. 1<= timeout <=63, default=60.
> -nowayout: Watchdog cannot be stopped once started
> + wdt_stop:
> + Advantech WDT 'stop' io port (default 0x443)
> + wdt_start:
> + Advantech WDT 'start' io port (default 0x443)
> + timeout:
> + Watchdog timeout in seconds. 1<= timeout <=63, default=60.
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> alim1535_wdt:
> -timeout: Watchdog timeout in seconds. (0 < timeout < 18000, default=60
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (0 < timeout < 18000, default=60
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> alim7101_wdt:
> -timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30
> -use_gpio: Use the gpio watchdog (required by old cobalt boards).
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=3600, default=30
> + use_gpio:
> + Use the gpio watchdog (required by old cobalt boards).
> default=0/off/no
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ar7_wdt:
> -margin: Watchdog margin in seconds (default=60)
> -nowayout: Disable watchdog shutdown on close
> + margin:
> + Watchdog margin in seconds (default=60)
> + nowayout:
> + Disable watchdog shutdown on close
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> armada_37xx_wdt:
> -timeout: Watchdog timeout in seconds. (default=120)
> -nowayout: Disable watchdog shutdown on close
> + timeout:
> + Watchdog timeout in seconds. (default=120)
> + nowayout:
> + Disable watchdog shutdown on close
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> at91rm9200_wdt:
> -wdt_time: Watchdog time in seconds. (default=5)
> -nowayout: Watchdog cannot be stopped once started
> + wdt_time:
> + Watchdog time in seconds. (default=5)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> at91sam9_wdt:
> -heartbeat: Watchdog heartbeats in seconds. (default = 15)
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeats in seconds. (default = 15)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> bcm47xx_wdt:
> -wdt_time: Watchdog time in seconds. (default=30)
> -nowayout: Watchdog cannot be stopped once started
> + wdt_time:
> + Watchdog time in seconds. (default=30)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> coh901327_wdt:
> -margin: Watchdog margin in seconds (default 60s)
> + margin:
> + Watchdog margin in seconds (default 60s)
> +
> -------------------------------------------------
> +
> cpu5wdt:
> -port: base address of watchdog card, default is 0x91
> -verbose: be verbose, default is 0 (no)
> -ticks: count down ticks, default is 10000
> + port:
> + base address of watchdog card, default is 0x91
> + verbose:
> + be verbose, default is 0 (no)
> + ticks:
> + count down ticks, default is 10000
> +
> -------------------------------------------------
> +
> cpwd:
> -wd0_timeout: Default watchdog0 timeout in 1/10secs
> -wd1_timeout: Default watchdog1 timeout in 1/10secs
> -wd2_timeout: Default watchdog2 timeout in 1/10secs
> + wd0_timeout:
> + Default watchdog0 timeout in 1/10secs
> + wd1_timeout:
> + Default watchdog1 timeout in 1/10secs
> + wd2_timeout:
> + Default watchdog2 timeout in 1/10secs
> +
> -------------------------------------------------
> +
> da9052wdt:
> -timeout: Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> davinci_wdt:
> -heartbeat: Watchdog heartbeat period in seconds from 1 to 600, default 60
> + heartbeat:
> + Watchdog heartbeat period in seconds from 1 to 600, default 60
> +
> -------------------------------------------------
> +
> ebc-c384_wdt:
> -timeout: Watchdog timeout in seconds. (1<=timeout<=15300, default=60)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=15300, default=60)
> + nowayout:
> + Watchdog cannot be stopped once started
> +
> -------------------------------------------------
> +
> ep93xx_wdt:
> -nowayout: Watchdog cannot be stopped once started
> -timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=TBD)
> + nowayout:
> + Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=3600, default=TBD)
> +
> -------------------------------------------------
> +
> eurotechwdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -io: Eurotech WDT io port (default=0x3f0)
> -irq: Eurotech WDT irq (default=10)
> -ev: Eurotech WDT event type (default is `int')
> + io:
> + Eurotech WDT io port (default=0x3f0)
> + irq:
> + Eurotech WDT irq (default=10)
> + ev:
> + Eurotech WDT event type (default is `int`)
> +
> -------------------------------------------------
> +
> gef_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> geodewdt:
> -timeout: Watchdog timeout in seconds. 1<= timeout <=131, default=60.
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. 1<= timeout <=131, default=60.
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> i6300esb:
> -heartbeat: Watchdog heartbeat in seconds. (1<heartbeat<2046, default=30)
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeat in seconds. (1<heartbeat<2046, default=30)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> iTCO_wdt:
> -heartbeat: Watchdog heartbeat in seconds.
> + heartbeat:
> + Watchdog heartbeat in seconds.
> (2<heartbeat<39 (TCO v1) or 613 (TCO v2), default=30)
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> iTCO_vendor_support:
> -vendorsupport: iTCO vendor specific support mode, default=0 (none),
> + vendorsupport:
> + iTCO vendor specific support mode, default=0 (none),
> 1=SuperMicro Pent3, 2=SuperMicro Pent4+, 911=Broken SMI BIOS
> +
> -------------------------------------------------
> +
> ib700wdt:
> -timeout: Watchdog timeout in seconds. 0<= timeout <=30, default=30.
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. 0<= timeout <=30, default=30.
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ibmasr:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> imx2_wdt:
> -timeout: Watchdog timeout in seconds (default 60 s)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds (default 60 s)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> indydog:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> iop_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> it8712f_wdt:
> -margin: Watchdog margin in seconds (default 60)
> -nowayout: Disable watchdog shutdown on close
> + margin:
> + Watchdog margin in seconds (default 60)
> + nowayout:
> + Disable watchdog shutdown on close
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> it87_wdt:
> -nogameport: Forbid the activation of game port, default=0
> -nocir: Forbid the use of CIR (workaround for some buggy setups); set to 1 if
> + nogameport:
> + Forbid the activation of game port, default=0
> + nocir:
> + Forbid the use of CIR (workaround for some buggy setups); set to 1 if
> system resets despite watchdog daemon running, default=0
> -exclusive: Watchdog exclusive device open, default=1
> -timeout: Watchdog timeout in seconds, default=60
> -testmode: Watchdog test mode (1 = no reboot), default=0
> -nowayout: Watchdog cannot be stopped once started
> + exclusive:
> + Watchdog exclusive device open, default=1
> + timeout:
> + Watchdog timeout in seconds, default=60
> + testmode:
> + Watchdog test mode (1 = no reboot), default=0
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ixp4xx_wdt:
> -heartbeat: Watchdog heartbeat in seconds (default 60s)
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeat in seconds (default 60s)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ks8695_wdt:
> -wdt_time: Watchdog time in seconds. (default=5)
> -nowayout: Watchdog cannot be stopped once started
> + wdt_time:
> + Watchdog time in seconds. (default=5)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> machzwd:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -action: after watchdog resets, generate:
> + action:
> + after watchdog resets, generate:
> 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI
> +
> -------------------------------------------------
> +
> max63xx_wdt:
> -heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 60
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeat period in seconds from 1 to 60, default 60
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -nodelay: Force selection of a timeout setting without initial delay
> + nodelay:
> + Force selection of a timeout setting without initial delay
> (max6373/74 only, default=0)
> +
> -------------------------------------------------
> +
> mixcomwd:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> mpc8xxx_wdt:
> -timeout: Watchdog timeout in ticks. (0<timeout<65536, default=65535)
> -reset: Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in ticks. (0<timeout<65536, default=65535)
> + reset:
> + Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> mv64x60_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ni903x_wdt:
> -timeout: Initial watchdog timeout in seconds (0<timeout<516, default=60)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Initial watchdog timeout in seconds (0<timeout<516, default=60)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> nic7018_wdt:
> -timeout: Initial watchdog timeout in seconds (0<timeout<464, default=80)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Initial watchdog timeout in seconds (0<timeout<464, default=80)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> nuc900_wdt:
> -heartbeat: Watchdog heartbeats in seconds.
> + heartbeat:
> + Watchdog heartbeats in seconds.
> (default = 15)
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> omap_wdt:
> -timer_margin: initial watchdog timeout (in seconds)
> -early_enable: Watchdog is started on module insertion (default=0
> -nowayout: Watchdog cannot be stopped once started
> + timer_margin:
> + initial watchdog timeout (in seconds)
> + early_enable:
> + Watchdog is started on module insertion (default=0
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> orion_wdt:
> -heartbeat: Initial watchdog heartbeat in seconds
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Initial watchdog heartbeat in seconds
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> pc87413_wdt:
> -io: pc87413 WDT I/O port (default: io).
> -timeout: Watchdog timeout in minutes (default=timeout).
> -nowayout: Watchdog cannot be stopped once started
> + io:
> + pc87413 WDT I/O port (default: io).
> + timeout:
> + Watchdog timeout in minutes (default=timeout).
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> pika_wdt:
> -heartbeat: Watchdog heartbeats in seconds. (default = 15)
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeats in seconds. (default = 15)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> pnx4008_wdt:
> -heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 19
> -nowayout: Set to 1 to keep watchdog running after device release
> + heartbeat:
> + Watchdog heartbeat period in seconds from 1 to 60, default 19
> + nowayout:
> + Set to 1 to keep watchdog running after device release
> +
> -------------------------------------------------
> +
> pnx833x_wdt:
> -timeout: Watchdog timeout in Mhz. (68Mhz clock), default=2040000000 (30 seconds)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in Mhz. (68Mhz clock), default=2040000000 (30 seconds)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -start_enabled: Watchdog is started on module insertion (default=1)
> + start_enabled:
> + Watchdog is started on module insertion (default=1)
> +
> -------------------------------------------------
> +
> rc32434_wdt:
> -timeout: Watchdog timeout value, in seconds (default=20)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout value, in seconds (default=20)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> riowd:
> -riowd_timeout: Watchdog timeout in minutes (default=1)
> + riowd_timeout:
> + Watchdog timeout in minutes (default=1)
> +
> -------------------------------------------------
> +
> s3c2410_wdt:
> -tmr_margin: Watchdog tmr_margin in seconds. (default=15)
> -tmr_atboot: Watchdog is started at boot time if set to 1, default=0
> -nowayout: Watchdog cannot be stopped once started
> + tmr_margin:
> + Watchdog tmr_margin in seconds. (default=15)
> + tmr_atboot:
> + Watchdog is started at boot time if set to 1, default=0
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -soft_noboot: Watchdog action, set to 1 to ignore reboots, 0 to reboot
> -debug: Watchdog debug, set to >1 for debug, (default 0)
> + soft_noboot:
> + Watchdog action, set to 1 to ignore reboots, 0 to reboot
> + debug:
> + Watchdog debug, set to >1 for debug, (default 0)
> +
> -------------------------------------------------
> +
> sa1100_wdt:
> -margin: Watchdog margin in seconds (default 60s)
> + margin:
> + Watchdog margin in seconds (default 60s)
> +
> -------------------------------------------------
> +
> sb_wdog:
> -timeout: Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)
> + timeout:
> + Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)
> +
> -------------------------------------------------
> +
> sbc60xxwdt:
> -wdt_stop: SBC60xx WDT 'stop' io port (default 0x45)
> -wdt_start: SBC60xx WDT 'start' io port (default 0x443)
> -timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
> -nowayout: Watchdog cannot be stopped once started
> + wdt_stop:
> + SBC60xx WDT 'stop' io port (default 0x45)
> + wdt_start:
> + SBC60xx WDT 'start' io port (default 0x443)
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sbc7240_wdt:
> -timeout: Watchdog timeout in seconds. (1<=timeout<=255, default=30)
> -nowayout: Disable watchdog when closing device file
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=255, default=30)
> + nowayout:
> + Disable watchdog when closing device file
> +
> -------------------------------------------------
> +
> sbc8360:
> -timeout: Index into timeout table (0-63) (default=27 (60s))
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Index into timeout table (0-63) (default=27 (60s))
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sbc_epx_c3:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sbc_fitpc2_wdt:
> -margin: Watchdog margin in seconds (default 60s)
> -nowayout: Watchdog cannot be stopped once started
> + margin:
> + Watchdog margin in seconds (default 60s)
> + nowayout:
> + Watchdog cannot be stopped once started
> +
> -------------------------------------------------
> +
> sbsa_gwdt:
> -timeout: Watchdog timeout in seconds. (default 10s)
> -action: Watchdog action at the first stage timeout,
> + timeout:
> + Watchdog timeout in seconds. (default 10s)
> + action:
> + Watchdog action at the first stage timeout,
> set to 0 to ignore, 1 to panic. (default=0)
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sc1200wdt:
> -isapnp: When set to 0 driver ISA PnP support will be disabled (default=1)
> -io: io port
> -timeout: range is 0-255 minutes, default is 1
> -nowayout: Watchdog cannot be stopped once started
> + isapnp:
> + When set to 0 driver ISA PnP support will be disabled (default=1)
> + io:
> + io port
> + timeout:
> + range is 0-255 minutes, default is 1
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sc520_wdt:
> -timeout: Watchdog timeout in seconds. (1 <= timeout <= 3600, default=30)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (1 <= timeout <= 3600, default=30)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sch311x_wdt:
> -force_id: Override the detected device ID
> -therm_trip: Should a ThermTrip trigger the reset generator
> -timeout: Watchdog timeout in seconds. 1<= timeout <=15300, default=60
> -nowayout: Watchdog cannot be stopped once started
> + force_id:
> + Override the detected device ID
> + therm_trip:
> + Should a ThermTrip trigger the reset generator
> + timeout:
> + Watchdog timeout in seconds. 1<= timeout <=15300, default=60
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> scx200_wdt:
> -margin: Watchdog margin in seconds
> -nowayout: Disable watchdog shutdown on close
> + margin:
> + Watchdog margin in seconds
> + nowayout:
> + Disable watchdog shutdown on close
> +
> -------------------------------------------------
> +
> shwdt:
> -clock_division_ratio: Clock division ratio. Valid ranges are from 0x5 (1.31ms)
> + clock_division_ratio:
> + Clock division ratio. Valid ranges are from 0x5 (1.31ms)
> to 0x7 (5.25ms). (default=7)
> -heartbeat: Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> smsc37b787_wdt:
> -timeout: range is 1-255 units, default is 60
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + range is 1-255 units, default is 60
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> softdog:
> -soft_margin: Watchdog soft_margin in seconds.
> + soft_margin:
> + Watchdog soft_margin in seconds.
> (0 < soft_margin < 65536, default=60)
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -soft_noboot: Softdog action, set to 1 to ignore reboots, 0 to reboot
> + soft_noboot:
> + Softdog action, set to 1 to ignore reboots, 0 to reboot
> (default=0)
> +
> -------------------------------------------------
> +
> stmp3xxx_wdt:
> -heartbeat: Watchdog heartbeat period in seconds from 1 to 4194304, default 19
> + heartbeat:
> + Watchdog heartbeat period in seconds from 1 to 4194304, default 19
> +
> -------------------------------------------------
> +
> tegra_wdt:
> -heartbeat: Watchdog heartbeats in seconds. (default = 120)
> -nowayout: Watchdog cannot be stopped once started
> + heartbeat:
> + Watchdog heartbeats in seconds. (default = 120)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> ts72xx_wdt:
> -timeout: Watchdog timeout in seconds. (1 <= timeout <= 8, default=8)
> -nowayout: Disable watchdog shutdown on close
> + timeout:
> + Watchdog timeout in seconds. (1 <= timeout <= 8, default=8)
> + nowayout:
> + Disable watchdog shutdown on close
> +
> -------------------------------------------------
> +
> twl4030_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> txx9wdt:
> -timeout: Watchdog timeout in seconds. (0<timeout<N, default=60)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (0<timeout<N, default=60)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> uniphier_wdt:
> -timeout: Watchdog timeout in power of two seconds.
> + timeout:
> + Watchdog timeout in power of two seconds.
> (1 <= timeout <= 128, default=64)
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> w83627hf_wdt:
> -wdt_io: w83627hf/thf WDT io port (default 0x2E)
> -timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
> -nowayout: Watchdog cannot be stopped once started
> + wdt_io:
> + w83627hf/thf WDT io port (default 0x2E)
> + timeout:
> + Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> w83877f_wdt:
> -timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> w83977f_wdt:
> -timeout: Watchdog timeout in seconds (15..7635), default=45)
> -testmode: Watchdog testmode (1 = no reboot), default=0
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds (15..7635), default=45)
> + testmode:
> + Watchdog testmode (1 = no reboot), default=0
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> wafer5823wdt:
> -timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> wdt285:
> -soft_margin: Watchdog timeout in seconds (default=60)
> + soft_margin:
> + Watchdog timeout in seconds (default=60)
> +
> -------------------------------------------------
> +
> wdt977:
> -timeout: Watchdog timeout in seconds (60..15300, default=60)
> -testmode: Watchdog testmode (1 = no reboot), default=0
> -nowayout: Watchdog cannot be stopped once started
> + timeout:
> + Watchdog timeout in seconds (60..15300, default=60)
> + testmode:
> + Watchdog testmode (1 = no reboot), default=0
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> wm831x_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> wm8350_wdt:
> -nowayout: Watchdog cannot be stopped once started
> + nowayout:
> + Watchdog cannot be stopped once started
> (default=kernel config parameter)
> +
> -------------------------------------------------
> +
> sun4v_wdt:
> -timeout_ms: Watchdog timeout in milliseconds 1..180000, default=60000)
> -nowayout: Watchdog cannot be stopped once started
> --------------------------------------------------
> + timeout_ms:
> + Watchdog timeout in milliseconds 1..180000, default=60000)
> + nowayout:
> + Watchdog cannot be stopped once started
> diff --git a/Documentation/watchdog/watchdog-pm.txt b/Documentation/watchdog/watchdog-pm.txt
> index 7a4dd46e0d24..646e1f28f31f 100644
> --- a/Documentation/watchdog/watchdog-pm.txt
> +++ b/Documentation/watchdog/watchdog-pm.txt
> @@ -1,5 +1,7 @@
> +===============================================
> The Linux WatchDog Timer Power Management Guide
> ===============================================
> +
> Last reviewed: 17-Dec-2018
>
> Wolfram Sang <wsa+renesas@...g-engineering.com>
> @@ -16,4 +18,5 @@ On resume, a watchdog timer shall be reset to its selected value to give
> userspace enough time to resume. [1] [2]
>
> [1] https://patchwork.kernel.org/patch/10252209/
> +
> [2] https://patchwork.kernel.org/patch/10711625/
> diff --git a/Documentation/watchdog/wdt.txt b/Documentation/watchdog/wdt.txt
> index ed2f0b860869..d97b0361535b 100644
> --- a/Documentation/watchdog/wdt.txt
> +++ b/Documentation/watchdog/wdt.txt
> @@ -1,11 +1,14 @@
> +============================================================
> +WDT Watchdog Timer Interfaces For The Linux Operating System
> +============================================================
> +
> Last Reviewed: 10/05/2007
>
> - WDT Watchdog Timer Interfaces For The Linux Operating System
> - Alan Cox <alan@...rguk.ukuu.org.uk>
> +Alan Cox <alan@...rguk.ukuu.org.uk>
>
> - ICS WDT501-P
> - ICS WDT501-P (no fan tachometer)
> - ICS WDT500-P
> + - ICS WDT501-P
> + - ICS WDT501-P (no fan tachometer)
> + - ICS WDT500-P
>
> All the interfaces provide /dev/watchdog, which when open must be written
> to within a timeout or the machine will reboot. Each write delays the reboot
> @@ -21,19 +24,26 @@ degrees Fahrenheit. Each read returns a single byte giving the temperature.
> The third interface logs kernel messages on additional alert events.
>
> The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to
> -pass IO address and IRQ boot parameters. E.g.:
> +pass IO address and IRQ boot parameters. E.g.::
> +
> wdt.io=0x240 wdt.irq=11
>
> Other "wdt" driver parameters are:
> +
> + =========== ======================================================
> heartbeat Watchdog heartbeat in seconds (default 60)
> nowayout Watchdog cannot be stopped once started (kernel
> - build parameter)
> + build parameter)
> tachometer WDT501-P Fan Tachometer support (0=disable, default=0)
> type WDT501-P Card type (500 or 501, default=500)
> + =========== ======================================================
>
> Features
> --------
> - WDT501P WDT500P
> +
> +================ ======= =======
> + WDT501P WDT500P
> +================ ======= =======
> Reboot Timer X X
> External Reboot X X
> I/O Port Monitor o o
> @@ -42,9 +52,12 @@ Fan Speed X o
> Power Under X o
> Power Over X o
> Overheat X o
> +================ ======= =======
>
> The external event interfaces on the WDT boards are not currently supported.
> Minor numbers are however allocated for it.
>
>
> -Example Watchdog Driver: see samples/watchdog/watchdog-simple.c
> +Example Watchdog Driver:
> +
> + see samples/watchdog/watchdog-simple.c
> --
> 2.20.1
>
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